Which IUD Is Right for You? Benefits, Side Effects, and More

So, you’ve decided you want an IUD — congratulations! There are five different IUDs to choose from, so how do you know which one is best for you?

Wait… back up. What’s an IUD?

An intrauterine device (IUD) is a type of long-acting reversible birth control that almost all women can use. It is a small, T-shaped device made of either plastic or copper that your health care provider inserts into your uterus to prevent pregnancy. Once placed, the IUD is more than 99 percent effective at preventing pregnancy for several years.

There are two main types of IUDs: nonhormonal and hormonal.

There is only one nonhormonal IUD available. It works by releasing small amounts of copper into the uterus, which stops sperm from fertilizing an egg. The four available hormonal IUDs contain levonorgestrel, which is a form of the hormone progestin. The IUD releases small amounts of the hormone into the uterus over time. The hormone prevents pregnancy by thickening cervical mucus, making it more difficult for sperm to reach the egg. It also thins the lining of the uterus.

With so many options now available, here are some things to consider about each one when making your choice.

ParaGard is the only nonhormonal IUD. It sometimes is called the copper IUD.

Lasts for: Ten years (although a recent study shows it is effective for up to 12 years)

Benefits: ParaGard is the longest-acting reversible form of birth control available. It’s a method of birth control that doesn’t use hormones, which is an important factor for some women, said Kristyn Brandi, M.D., F.A.C.O.G., a family planning specialist at Boston University and Boston Medical Center.

Possible side effects: ParaGard can make periods heavier and more painful, but usually these effects decrease within a year of use. “Someone that has light periods should expect no change or possibly a slightly heavier period,” Dr. Brandi said. “But for someone that has heavy periods, they may experience even heavier periods, so they may want to think about if this is a good option to them.”

Bonus: It also can act as emergency contraception if inserted within five days of unprotected sex, Dr. Brandi said.

Mirena is the hormonal IUD that has been on the market the longest. It contains 52 mg of progestin.

Lasts for: Five years (although a June 2016 study shows it is effective for up to seven years)

Benefits: Mirena can have effects on the menstrual period that some women like, Dr. Brandi said. “Women typically experience lighter periods or no periods at all,” she said. However, Dr. Brandi noted that some women may not view this as a benefit if they like having a monthly period for cultural reasons or to assure themselves they are not pregnant. Hormonal IUDs also may decrease menstrual pain. In fact, Mirena is the only IUD available that is approved specifically as a way to treat heavy periods.

Possible side effects: With all of the hormonal IUDs, you may see more spotting and irregular bleeding in the first three to six months of use. Like the side effects of the copper IUD, these side effects usually decrease over time, although periods may stay irregular. Other side effects may include headaches, nausea, depression, and breast tenderness, but these are not as common.

Skyla is a smaller IUD that has fewer hormones in it than Mirena. It contains 13.5 mg of progestin.

Lasts for: Three years

Benefits: “Some women like [using Skyla] because typically their periods are lighter but not necessarily absent,” Dr. Brandi said. For those who prefer not to make their period stop completely, this could be a good option, she said. Like Mirena, Skyla also may help decrease menstrual pain.

Possible side effects: Skyla has the same potential side effects as Mirena and the other hormonal IUDs.

Liletta is “essentially the same thing as Mirena,” said Dr. Brandi, but with a lower price tag. It contains the same amount of progestin (52 mg) as Mirena.

Benefits: “It was developed by a nonprofit pharmaceutical company, which is the first of its kind, which means the cost is much, much less,” Dr. Brandi said. Beyond that, Liletta has the same benefits as Mirena in terms of decreased menstrual pain and bleeding.

Possible side effects: Liletta has the same potential side effects as the other hormonal IUDs.

Kyleena is the newest IUD available (approved by the Food and Drug Administration in September 2016). It contains 19.5 mg of progestin.

Lasts for: Five years

Benefits: It has the effect of lightening periods or even stopping them over time, Dr. Brandi said. However, because it contains fewer hormones, it is not as likely as Mirena to stop periods completely (a 12 percent chance, compared with a 20 percent chance for Mirena).

Possible side effects: Kyleena has the same potential side effects as the other hormonal IUDs.

Lara is a digital editor for HealthCentral. She is the site’s staff writer, Sexual Health editor, and email newsletter chief. Previously, she worked as the patient education editor at the American College of OB-GYNs, where she became obsessed with learning about women’s health. She also freelances as a news writer/editor at WTOP.com. Connect with her on Twitter @laradesanto.